I bought this timer (see picture, sorry it is somewhat blurry) to replace a light switch to control a porch light. It seems fairly simple to install. It has two black wires, the directions say to take the two wires on the timer, twist together with the two wires from inside the wall and connect together with caps provided. My question is with both of these wires being black, and no indication of which is positive or negative, how do I know which wire on the timer gets connected to which wire inside my wall?

Adding a new window in exterior wall 16"oc. I plan to build a window frame for the 32" wide window after removing two existing studs giving me 48"oc of space. Doing it like this in the middle of the room, there it is an outlet box that is on the inside of the framing, ie, the 48" space has an outlet on the inside of the left stud. This complicates my simple plan to build a studded window frame and slide in between the 48" space. I really don't want to move the window to different studs because it will be off center. How would you recommend I deal with the outlet and existing wiring that would interfere with the window frame? If I move it to the outside of the stud, I'd have to reroute the wire thru the top plate (not desireable). Oh, and the inside of the wall has 3/8 sheathing (don't ask) so I didn't want to tear into that other than removing the 48" section. I need that outlet also. I hope this is understandable.